Did it occur to anyone that perhaps the hostages were released because their relatives davened to Hashem, and that He is a shomeah tefilah? Why make it into a Lubavitch centered thing? I guarantee that a heartfelt tefilah with השתפכות הנפש in a shul is better than mouthing words by a kever – any kever. Not that most people mouth words at kevarim, just that it isn’t the main thing. Also, i have no idea how many were released among those who went to the Lubavitcher rebbes kever. (I refuse to refer to him as “the rebbe” or his kever as “the ohel,” because i don’t think he was special among rebbes)
Similarly, the rescue of the last 2 hostages that were saved happened after their relatives took on mitzvos.